People with exsiting imperial gaurd armies. what is your thought on collecting the new Death Korp Mini?

As an existing guard player, I am very on the fence about whether to buy  and collect the new DKOK minis, I like the models themselves very much, but as someone who already has a large Cadian army, I am hesitant whether I want to buy or collect them due to potential rules or fluff integration with my current army.

Fluff wise, I don’t mind having infantry squads from other regiments in my regiments (DKoK / Catachans / Rough riders / scions ) as I can currently fluff them being niche specialists from other regiments, however, as the DKOK grow it I fear this may become a bit tricker to not envisage them as a complete separate regiment.

Another issue rules wise, is how viable a army that is a half or  third DKOK would be. I expect (correct me if I am right/wrong) that the new Lord Marshall and command squads will be focused on interacting with units with the DKOK key words, so I would assume that the design premise for DKOK will be for all non-vehicular units to DKOK, discouraging me from using my existing Cadian models and infantry.